             [:a {:class-name "mdl-navigation__link"
                  :href ""}
              [:i {:class-name "mdl-color-text--blue-grey-400 material-icons"
-                  :role "presentation"} "home"] "home"]]]
+                  :role "presentation"} "home"] "home"]
+            [:a {:class-name "mdl-navigation__link"
+                 :href ""}
+             [:i {:class-name "mdl-color-text--blue-grey-400 material-icons"
+                  :role "presentation"} "settings"] "settings"]]]
 
           [:main {:class-name "mdl-layout__content mdl-color--grey-100"}
            [:button {:on-click   #(go (>! debug :click))

  :on-mount   (fn [_ [id _] {:keys [sigma-ctrl]}] (go (>! sigma-ctrl (s/ctrl-update id))))
  :on-unmount (fn [_ [id _] {:keys [sigma-ctrl]}] (go (>! sigma-ctrl (s/ctrl-remove id))))
  [[id props] {:keys [drop-graph] :as intent-chans}]
  (html [:section {:class "graph-section"}
         [:button {:on-click #(go (>! drop-graph id))
                   :class-name "mdl-button mdl-js-button mdl-js-ripple-effect"} "delete " id]
         [:div {:id    (graph-id id)
                :class "graph"}]]))

(defcomponent Root
  [state {:keys [add-graph debug] :as intent-chans}]
  (html [:div {:id "plongeur-main"}
         [:div {:id         "layout"
                :class-name "demo-layout mdl-layout mdl-js-layout mdl-layout--fixed-drawer mdl-layout--fixed-header"}


           [:button {:on-click   #(go (>! add-graph :click))
                     :hidden     (>= (-> state :graphs count) 4)
                     :class-name "mdl-button mdl-js-button mdl-button--fab mdl-button--colored"}
            [:i {:class-name "material-icons"} "add"]]]]])

              )

(defn view
  "Returns a stream of view trees, represented as a core.async channel."
